1. Field of the Invention
This invention relates to a window glass washing system including at least one swingable wiper for washing a vehicle window glass with liquid detergent injected on the window glass. The invention is more particularly concerned with such a system capable of injecting liquid detergent intermittently in synchronism with swinging movement of the wiper so as to prevent the injected liquid detergent from striking on the wiper
2. Description of the Prior Art
A window glass washing system is normally incorporated in a vehicle such as an automotive vehicle for washing its front or rear window glass. Such a system includes at least one wiper swingable in sliding contact with the window glass for washing it with a liquid detergent injected thereon. If liquid detergent is continuously injected on the window glass during swinging movement of the wiper, however, it will strike on the wiper and scatter over a wide area of the window glass, which results in detergent economy penalty.
In order to prevent the injected liquid detergent from striking on the wiper, an improved window glass washing system has been proposed which is adapted to inject liquid detergent intermittently in synchronism with swinging movement of the wiper so as to stop the injection of liquid detergent when the wiper swings up or down around the position of the window glass at which the liquid detergent is injected. However, such a conventional system is insufficient in durability.